1. Field of the Invention
The present invention relates to a switching power supply circuit.
2. Description of Related Art
There is a conventional switching power supply circuit having a power factor improvement function (so-called power factor correction (PFC) function) in which a phase of an AC input voltage and a phase of an AC input current are adjusted so that the power factor becomes close to one. In addition, there is a conventional switching power supply circuit having a frequency hopping function (frequency spectrum spreading function) in which the switching frequency is periodically changed so that low electro-magnetic interference (EMI) is realized.
As an example of the conventional technique related to be above description, there is JP-A-2012-182967 filed by this applicant.
However, if both the power factor improvement function and the frequency hopping function are independently mounted in the conventional switching power supply circuit, even order harmonic characteristics may be deteriorated.